In spur gear stages with helical teeth, axial forces are produced which have to be absorbed by appropriately sized axial bearings. For this, conical-roller bearings are often used, which on the one hand are relatively expensive and on the other hand generate a relatively high heat output. It has therefore already been proposed, instead of costly axial bearings, to arrange so-termed pressure pads on spur gears having helical teeth, whereby the axial forces are absorbed. In the technical paper “Hydrodynamic axial force transmission in shafts of high-speed transmissions” by H. Langer, published in the journal Konstuktion 34 (1982), Vol. 12, pp. 473-478, such pressure pads are described. The known pressure pad is made as a separate, annular individual component (pressure ring) and is joined to the spur gear concerned, the spur gear and the pressure ring generally being connected to one another by a shrink fit. The pressure ring, which is attached in the middle or at the front end of the spur gear, preferably has conical faces which come into contact with corresponding contact faces of the mating gear, for example the groove flanks of a ring groove in the mating gear. Between the contact faces a lubricant film is formed. A disadvantage of the known pressure rings or pressure pads made as add-on components is that their attachment to the spur gear is not always reliable. Owing to the action of centrifugal force during operation, the shrink fit seating can become loose or fall apart.
From DE 1 215 463 a gear train with a helically toothed pinion is known, onto the middle of which a ring with conical contact surfaces is shrunk. The conical contact surfaces run against groove flanks of a ring groove positioned centrally in the two mating gears that mesh with the pinion. The ring, which can also be called a pressure pad, absorbs the axial forces resulting from the helical teeth so that corresponding axial bearings can be omitted.